This study carried out petrological and geochemical research on the mantle-derived peridotitic xenoliths borne in Cenozoic akali-basalts in Maguan, Yunnan Province, southwestern China. The results of five whole-rock Re-Os isotopic analysis show that the Os concentrations of the peridotitic xenoliths are relatively high(3.29×10-9~3.78×10-9), comparable to those of peridotite massif from orogenic belts, and the Re concentrations change in a relatively wide variation, ranging from 0.24×10-9 to 0.54×10-9.The 187Os/188Os ratios of samples vary between 0.122 95 and 0.125 30.Neither 187Re/188Os ratios nor Al2O3 contents show correlation with 187Os/188Os ratios, indicating that the Re-Os isotopic system is not solely controlled by melt extraction process.